In this lay reader's introduction to the most spectacular and devastating of all geological events, Rolf Schick describes how earthquakes and volcanoes are related, and how they are an integral part of Earth's structure. Tracing the latest findings and theories in plate tectonics, he helps readers ask and answer the basic questions: What was it during the formation of Earth that led to these phenomena? Why do they occur in certain areas and not in others? How can we, within reason, protect ourselves from their devastation?